I just returned from Good Friday service at my church. The Gospel was from John 18-19. John 19:14 says Jesus was crucified on the Day of Preparation for the Passover or at least, that was my understanding from the lesson. Then, I remembered that the Last Supper was on the night before He was crucified. Was not the Last Supper the same as the Passover?

The Gospel of John was arranged to convey a theological message, not to relay history. That is really true of all gospels, but we see this clearly in John, as he greatly departs from the others.

In the introduction, Jesus is declared by John the Baptist to be "The Lamb of God". Therefore Jesus, in John's gospel, becomes literally the lamb sacrificed for Passover. Later John's gospel has the high priest, declare that Jesus should die "for the nation". This is call a double entendre, it had a literal meaning, that Jesus should die to prevent the Roman's from destroying the nation, and a spiritual (hidden) meaning, that Jesus would be the Passover Lamb for the nation. Therefore Jesus could not be at the Passover, since he was the Passover Meal.